1. Field of the Invention
The subject invention relates to air filtration systems and more particularly to portable air filtration systems that may be modified between different configurations based on use and used in industrial environments to filter and re-circulate the fumes from a fume source.
2. Description of the Prior Art
Many factories use machines or equipment, in welding for example, which create unhealthy fumes that must be filtered. Back draft assemblies, and positionable fume arms have been used near the source of the fumes, e.g. the work-piece being welded.
Positionable fume arms often include a small hood and a fume arm. The hood is positioned near the fume source and the fume arm transfers the fumes to the housing where they are filtered. A low horsepower motor is used to drive a fan in these positionable arm systems. The hood of a fume must be placed no farther than eighteen inches from the fume source in order to be effective. In certain applications, for example when a large work-piece is being welded, the hood must be consistently moved along the work-piece to maintain adequate filtration of the fumes. Welders often neglect to move the hood because of the effort required to do so and because it breaks their concentration on the welding operation. Neglecting to consistently move the hood to keep it within the eighteen inch operating range thereby compromises the quality of air in the work environment.
A back draft housing includes a housing inlet for receiving the fumes and a housing outlet for dispensing the fumes. A motor and a fan operatively connected to the motor generates suction at the housing inlet and propels the fumes out of the housing through the housing outlet. A filter is disposed in the housing for filtering particulates from the fumes.
Back draft housings are very effective when used in, for example, welding cells. The back draft housing is usually floor mounted and is very powerful so that it can pull fumes from the welding cell. The problem with back draft housings is that they cannot be effectively used on long welds. The distance between the back draft housing and the point of the weld has to be in the unit's range, or it will be ineffective.